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3 years ago

When did most of the major groups of animals first appear during the paleozoic era?

1 answer:

6 0

Most major animal groups first appeared during the Cambrian Period (544 to 505 million years ago) during the Paleozoic era.
During the Cambrian period hard shelled animals appeared in great numbers for the first time, significantly because shallow seas flooded the continents. It is truly an astonishing period in evolution of life on earth. Most major groups of animals first appear in the fossil record, an event popularly and scientifically called the Cambrian Explosion.

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If you are really stressed out about an upcoming math test on Tuesday what type of stress is this? A: avoidance B:acute C:chroni

Kobotan [32]

Some students feel distressed only in test situations. They might be said to suffer from Acute Stress.

Answer: Option B

Explanation:

Stress is your body's reaction to specific circumstances. It's abstract, so something that is distressing for you may not be unpleasant for another person. There is a wide range of sorts of stress and not every one of them is terrible. Stress can enable you to act rapidly in a crisis or help you comply with a time constraint.

Acute stress is the most widely recognized sort of pressure. It's your body's prompt response to another test, occasion, or request, and it triggers your battle or flight reaction.

5 0

3 years ago

In humans, hemophilia is caused by an X-linked recessive gene. A woman who is a nonbleeder - that is, she does not display the b

wariber [46]

Answer:

one normal girl

One normal boy

One carrier girl

One colour blind boy

Explanation:

Haemophilia is a sex linked feature as it is transmitted with the chromosomes determining sex.

In humans,the male has XY and the female has XX.the Y chromosome is usually genetically empty.so as mall received his Y chromosomes from his father,he cannot inherit his father's sex linked traits .but women can as they receive and X chromosomes from their fathers.so a cross between a carrier woman Cc and a normal man C result in;

XX--CC

XX--Cc

XY--C

XY--c

7 0

3 years ago

List the layers of Earth’s atmosphere in order of increasing altitude.

leva [86]

Answer:

Explanation:

These are the correct layers in order of increasing altitude.

8 0

3 years ago

Read 2 more answers

hey, can u help me with the following questions but write it descriptively and briefly describe and if u can write it on your ow

Novay_Z [31]

Answer:

Answer to 1: a black hole is a tremendous amount of matter crammed into a very small (zero) amount of space. Answer to 2: the top of your head would feel so much more gravitational pull than the tips of your toes that you would be stretched, longer and longer Answer to 3: A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. because no light can get out, people can't see black holes Answer to 4: stellar, intermediate, supermassive, and miniature. Answer to 5: the asymmetry of bright and dark sections of the ring are caused by the Doppler effect as the matter is coming toward Earth (brighter) or receding (dimmer).

Explanation:

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4 years ago

Which mechanism of genetic variation results from the exchange of gene segments between non-sister chromatids?

valentinak56 [21]

Crossing over is the mechanism of genetic variation results from the exchange of gene segments between non-sister chromatids.

5 0

4 years ago

Read 2 more answers